Strainer apparatus



May 13, 1958 M. J. JALKANEN STRAINER APPARATUS 4 Sheets-Sheet 2 Filed y12. 1954 FlG.4

STRAINER APPARATUS Matti Johannes Jalkanen, Rauma, Finland, assigno'rtoRauma-Repola y, Rauma, Finland Application May 12, 1954, Serial No.429,308 Claims priority, application Finland May 28, 1953 20 Claims.(Cl. fill- 408) The present invention relates to strainer apparatus.More particularly, the invention relates to counter cu'rrent washtowers, counter-current thickener towers or countercurrentbleachingtowers adapted for treating sjlurries of fibrous matter such as asuspension of material as pulp and paper stock.

Washer and thickener devices of the above type are disclosed inapplicants co-pending application, Serial No. 324,934, filed December 9,1952, now Patent No. 2,802,- 572, of which this application is acontinuation-impart, the present invention being an improvement on' suchtypes of Washers and thickeners.

it is an object of the present invention to provide strainer devices inapparatus of. the above types inwhich means are provided for freeing thestrainer of deposited solid material which tends to clog the strainer.

It is another object of the present invention to provide for improvedstraining in apparatus of the above types.

With the above objects in view, the present invention relates to astrainer apparatus which comprises, in combination, strainer meanshaving a first face on which a suspension ofsolid material to bestrained is deposited, the filtrate passing in one direction through thestrainer means to the second face thereof and a deposit of solidmaterial remaining on the first face of the strainer means, doctor meansarranged adjacent the first face of the strainer means and having acleaning edge extending along the same, moving means moving one of themeans relative to the other with the cleaning edge of the doctor meansmovingrelative to and along the first face of the strainer means, andloosening means for forcing filtrate which has passed in theonedirection through the strainer means back in the opposite directionfrom the second face through thestrainer means to the first face thereofand in front of the cleaning edge of the doctor means, the looseningmeans being mounted in a position fixed relative to the doctor means forforcing filtrate out ofthe first face of the strainer means at aconstant distance from the cleaning edge of the doctor meansduringmovement thereof relative to the strainer means, so-asto therebyloosen the deposit ofsolid material on the first face of the strainermeans.

in accordance with the invention,-either the doctor means may be rotatedrelative to a stationary strainer means, or the strainer means may berotated relative to a fixeddoctor-means.

The strainer means in the device constructed in-accordance with theinvention is preferably formed with wall portions enclosing the secondface thereof soas to form a plurality of cells communicating withdifferent portions of the first face thereof, the loosening meansincluding conduit means communicating successivelywith the plurality ofcells during relative movement of the strainer means and the doctormeans.

In accordance with the invention, a filtrate chamber is preferablyarranged adjacent the strainermeans for collecting the filtrate passingtherethrough, the loosening means being connected to the filtratechamber for reintroducing a portion of the filtrate therein back througlthe strainer means, and the filtrate chamber having an outlet fordischarging the remainder of the filtrate.

The novel features which are considered as characteristic for theinvention are set forth in particular in the appended claims. Theinvention itself, however, both as to its construction and its method ofoperation, together with additional objects and advantages thereof, willbe best understood from the following description of specificembodiments when read in connection with the accompanying drawings, inwhich:

Fig. 1 is a diagrammatic view illustrating the cleaning principle inaccordance with the invention;

Fig. 2 is a vertical sectional view of one embodiment of an apparatusconstructed in accordance with the invention;

Fig. 3 is a horizontal sectional view taken along the line III-III ofFig. 2;

Fig. 4 is a horizontalsectional view taken along the line lV-lV of Fig.2;

Fig. 5 is a vertical sectional view taken along the line VV of Fig. 2;

Fig. 6 is a vertical sectional view of another embodiment of theinvention;

Fig. 7 is a horizontal sectional view taken along the line VlI--VII ofFig. 6; and

Fig. 8 is a vertical sectional view of still another embodiment oftheinvention. A

' Referring now to the drawings, and particularly to Fig. 1, there isshown in the latter figure a strainer wall In and a doctor means 4a, thestrainer wall 1a being movable in the direction of the arrow a relativeto the doctor means 4a. Arranged on one side of the strainer wall 1a isa slurry receiving container means 2a in which there is shown thickenedsolid matter tin-deposited on the upper face of strainer wall 1a. Aslurry inlet 5a serves to conduct slurry into the container 2a andbeneath the doctor means 40, via inlet channel 17a. On the other side ofstrainer wall 1a there is arranged a filtrate collecting chamber 3a,having an outlet 6a connected thereto and a-conduit in which pump 7a isarranged for returning part of the filtrate back to the strainer wall 1avia a shoe or spout member 8a.

When slurry is introduced via inlet 5a intothe inlet channel 17a andtherefrom into the container means 2a,

liquid will pass through the strainer wall 1a into the filtratecollecting chamber 3a as indicated by arrows 17, while solid matter, e.g., fibrous material, will thicken and form a layer on the surface ofthe strainer wall In.

In accordance with the invention, one part of the liquid collecting inthe chamber 3a is discharged to the outside via outlet 6a, while asecond part of the liquid is reintroduced in reverse flow by means ofthe pump 7a and the spout member 8a into the slurry container 2a throughthat portion of the strainer wall 1a which is positioned directly infront of the leading edge 15a of the doctor means 4a, as is shown byarrows c. When the pump pressure is so selected that it always overcomesthe pressure prevailing in the slurry container 2a,'-the recycledcleaning liquid will be forced through the strainer wall portion infront of the leading edge 15a, and in doing this it will lift the solidmatter collected thereon onto the leading edge 15a of doctor means 4a,and from this point the solid material will slide over the top surfaceof the doctor means and upon the fresh slurry fed continuously onto theclean portion of the strainer wall 1a.

In the embodiment shown in Figs. 2-5, the strainer walll within thetower18 is stationary while the spout member. 8 for distributing the recycledcleaning liquid and the doctor means 4 are arranged for movement withthe rotatable vertical shaft 10 which is provided with agitator arms 23.The strainer wall 1 rests on supporting walls 19 arranged so as to forma series of cells 12 under the strainer wall 1. The strained liquidpassing through strainer wall 1 is adapted to be conducted through thecells 12 into the filtrate collecting chamber 3 which is also locatedbeneath the strainer wall 1 and is encircled by the filtrate collectingcells 12, the filtrate chamber 3 having apertures 22 in the wall thereofcommunicating with the individual cells for the passage of liquidtherethrough.

The spout member 8 is arranged to rotate with the shaft 10 and tocommunicate with the filtrate collecting chamber 3 via the tubular lowerend 28 of the shaft 10, the pump 7, the pressure pipe 27 and the suctionpipe 26. Spout member 8 during such rotation moves within the chamber 3so that each of the cells 12 consecutively communicates via theapertures 22 with the outlet end of the spout member 8, while the restof the cells 12 all communicate with the collecting chamber 3.

As shown more clearly in Fig. 3, the doctor means 4 when viewed in planis sector-shaped. The leading part of doctor means 4 consists of aninclined surface 15 serving as a blade or doctor proper and a topsurface 4b, the surfaces 15 and 4b with strainer wall 1 defining aninlet channel 17 within the doctor means 4 for accommodating the slurry.For the purpose of introducing slurry into the inlet channel 17, anannular slurry inlet duct 13 is arranged in the bottom part of tower 18above the strainer wall 1. Inlet conduit serves to introduce slurry intothe duct 13, from which it is discharged through slot 14 in the bottompart of duct 13 into the slurry inlet channel 17 within doctor means 4,as indicated by arrow d in Fig. 3. A projecting member 16 is secured tothe periphery of doctor means 4 and during rotation of the doctor meansserves to guide the movement of fresh slurry introduced into annularduct 13 underneath doctor means 4.

The above-described apparatus operates as follows:

When a slurry ,or other suspension of solid material, e. g., pulp stock,is fed into the doctor means 4, it spreads within the container formedby tower 18 upon strainer wall 1 while liquid separates therefromthrough the strainer wall 1 and passes therethrough via cells 12 intothe filtrate collecting chamber 3. The most effective liquid separationand deposition of fibrous matter occurs at that portion of the strainerwall which is cleaned by the doctor blade 15, and the filtered liquidissues from under doctor blade 15 when the same moves forward along thestrainer wall 1. When the doctor means 4 passes further over thestrainer wall 1, thickened fibrous matter will remain deposited on thestrainer wall and is subjected to the pressure of the pulp already inthe tower 18, and liquid will continue to separate therefrom and passinto filtrate chamber 3 for the reason that when doctor means 4 movesforward, previously deposited matter will glide along and over the topsurface of doctor means 4 until it drops over the trailing edge of thedoctor means and settles upon the new layer of matter issuing from theinlet channel 17 within the doctor means 4.

The annular duct 13 may be replaced by an inlet pipe arranged to passthrough vertical shaft 10 and terminating in the inlet channel 17 ofdoctor means 4.

In the embodiment shown in Figs. 6 and 7, the strainer wall 1 is securedto the drive shaft 10 and arranged to rotate relative to the stationarydoctor means 4 and the ture 24 so that during rotation of the strainerWall 1' 4 together with its supporting structure 19' each cell 12' willconsecutively communicate with the spout member 8', While the remainderof the cells 12 will concurrently communicate with the filtratecollecting chamber 3 which encircles the apertured cell portions.

As in the first-described embodiment, here also one part of'the filtratecollected in chamber 3 is discharged to the outside via pipe 6', while asecond part of the filtrate is recycled, by means of the pump 7' and thespout member 8', in the manner previously described through the strainerwall 1 into the slurry container. Fresh slurry is introduced via theinlet conduit 5' directly into the inlet channel 17' of the doctormeans, the slurry passing therefrom into the container means 2, becausethe rotatably mounted strainer wall 1' renders the annular slurry inletduct 13 superfluous.

The embodiment shown in Fig. 8 differs from the one shown in Figs. 2-5in that the filtrate collecting cells 12" which are located underneaththe strainer wall 1" are connected by conduits 24" to a separatefiltrate collecting chamber 3". The advantageof this embodiment residesin the relative simplicity of its construction, the arrangement of theparts thereof rendering it easy to manipulate and maintain in operation.

The embodiment shown in the drawings and described above are given onlyby way of example merely to illustrate the concept involved in theinvention, and it is to be understood that the invention is not limitedto the .embodiments shown. Thus, for example, the strainer wall meansmay be arranged in a manner other than as described above, as, forinstance, by utilizing as a strainer wall a cylindrical screen'arrangedin a vertical position within the container means. In such a form, thedoctor means is advantageously arranged within the cylindrical screenwhile recycled liquid under pressure is re-introduced into thecylindrical screen through ducts arranged between the the screencylinder and the filtrate collecting chamber.

The invention also contemplates the arrangement of the strainer means inthe upper portion of the container means, or, if the container means ishorizontal, the strainer means could be arranged in one end of thecontainer means while any suitable means is employed for producing thepressure differences required for liquid transfer. The invention alsocontemplates the use of one or more doctor means as well as a pluralityof spout members arranged to cooperate with one and the same strainerstructure and the associated parts.

It will be understood that each of the elements described above, or twoor more together, may also find a useful application in other types ofapparatus for treating suspensions of solid matter differing from thetypes described above.

While the invention has been illustrated and described 'as embodied in astrainer apparatus for treating slurry, it is not intended to be limitedto the details shown, since various modifications and structural changesmay be made without departing in any way from the spirit of presentinvention. I Without further analysis, the foregoing will so fullyreveal the gist of the present invention that others can by applyingcurrent knowledge readily adapt it for various applications Withoutomitting features that, from the standpoint of prior art, fairlyconstitute essential characteristicsof the generic or specific aspectsof this invention and, therefore, such adaptations should and areintended to be comprehended within the meaning and range of equivalenceof the following claims.

What-is claimed as new and desired to be secured by Letters Patent is:

I 1. In a strainer apparatus, in combination, an upright container;strainer means arranged near the bottom of said container and'having ahorizontal first upwardly directed face on which a suspension of solidmaterial to asses-74 be strained is deposited, the filtrate passing'inone direction through said strainer means to the second face thereof anda deposit of strained solid material remaining on said first face ofsaid strainer means; doctor means arranged adjacent said first face ofsaid strainer means and having a cleaning edge extending along the same;moving means moving one of said means relative to the other With saidcleaning edge of said doctor means moving relative to and along saidfirst face of said strainer means; and loosening means for forcingfiltrate which has passed in said one direction through said strainermeans back in the opposite direction from said second face through saidstrainer means to said first face thereof and in front of said cleaningedge of said doctor means, said loosening means being mounted in aposition relative to said doctor means for forcing filtrate out of saidfirst face of said strainer means in front of the cleaning edge of saiddoctor means during movement thereof relative to said strainer means, soas to thereby loosen said deposit of solid material on said first faceof said strainer means whereby the strained solid material accumulatesin said upright container to apply pressure to the suspension of solidmaterial deposited on said horizontal first face.

2. In a strainer apparatus, in combination, an upright container;strainer means arranged near the bottom of said container and having ahorizontal first upwardly directed face on which a suspension of solidmaterial to be strained is deposited, the filtrate passing in onedirection through said strainer means to the second face thereof and adeposit of strained solid material remaining .on said first face of saidstrainer means; doctor means arranged adjacent said first face of saidstrainer means and having a cleaning edge extending along the same;rotating means rotating one of said means relative to the other withsaid cleaning edge of said doctor means moving relative to and alongsaid first-face of said strainer means; and loosening means for forcingfiltrate which has passed in said one'direction through said strainermeans back in the opposite direction from said second face through saidstrainer means to said first face thereof and in front of said cleaningedge of said doctor means, said loosening means being mounted in aposition relative to said doctor means for forcing filtrate out of saidfirst face of said strainer means in front of the cleaning'edge of saiddoctor means during movement thereof relative to said strainer means, soas to thereby loosen said deposit of solid material on said first faceof said strainer means whereby the strained solid material accumulatesin said upright container to apply pressure to the suspension of solidmaterial deposited on said horizontal front face.

3. In a strainer apparatus, in combination, an upright container;strainer means arranged near the bottom of said container and having ahorizontal first upwardly directed face on which a suspension of solidmaterial to be strained is deposited, the filtrate passing in onedirection through said strainer means to the second face thereof and adeposit of strained solid material remaining on said first face of saidstrainer means; doctor means arranged adjacent said first face of saidstrainer means and having a cleaning edge extending along the same;rotating means rotating said doctor means relative to said strainermeans with said cleaning edge of said doctor means moving relative toand along said firstface of said strainer means; and loosening means forforcing filtrate which has passed in said one direction through saidstrainer means back in the opposite direction from said second facethrough said strainer means to said first face thereof andin front ofsaid cleaning edge of said doctor means, said loosening means beingmounted in a position relative to said doctor means for forcing filtrateout of said first face of said strainer means in front of the clean ingedge of said doctor means during movement thereof relative tosaidstrainer means, so as to thereby loosen said deposit of solid materialon said first face of said strainer means whereby the strained solidmaterial accu- 6 mulates in said upright container to'apply pressure tothe suspension of solid materialdeposited on said horizontal first face.

4. In a strainer apparatus, in combination, an upright container;strainer means arranged near the bottom of said container and having ahorizontal first upwardly directed face on which a suspension of solidmaterial to be strained is deposited, the filtrate passing in onedirection through. said strainer means to the second face thereof and adeposit of strained solid material remaining on said first face of saidstrainer means; doctor means arranged adjacent said first face of saidstrainer means and having a cleaning edge extending along the same;rotating means rotating said strainer means relative to said doctormeans with said cleaning edge of said doctor means moving relative toand along said firstface of said strainer means; and loosening means forforcing filtrate which has passed in said one direction through saidstrainer means back in the opposite direction from said second facethrough said strainer means to said first face thereof and in front ofsaid cleaning edge of said doctor means, said loosening means beingmounted in a position relative to said doctor means for forcing filtrateout of said first face of said strainer means in front of the cleaningedge of said doctor means, during movement thereof relative to saidstrainer means, so as to thereby loosen said deposit of solid materialon said first face of said strainer means whereby the strained solidmaterial accumulates in said upright container to apply pressure to thesuspension of solid material deposited on said horizontal first face.

5. In a strainer apparatus, in combination, an upright container;strainer means arranged near the bottom of said container and having ahorizontal first upwardly directed face on which a suspension of solidmaterial to be strained is deposited, the filtrate passing in onedirection through said strainer means to the second face thereof and adeposit of strained solid material remaining on said first face of saidstrainer means, said-strainer means having wall portions enclosing saidsecond face thereof and forming therewith a plurality of cellscommunicating with different portions of the first face thereof; doctormeans arranged adjacent said first face of said strainer means andhaving a cleaning edge extending along the same; moving means moving oneof said means relative to the other with said cleaning edge of saiddoctor means moving relative to and along said first face of saidstrainer means; and loosening means for receiving filtrate which haspassed in said one direction through said strainer means and forcing itback in the opposite direction from said second face through saidstrainer means to said first face thereof and in front of said cleaningedge of said doctor means, said loosening means being mounted in aposition relative to said doctor means for forcing filtrate out of saidfirst face of said strainer means infront of the cleaning edge of saiddoctor means during movement thereof relative to said strainer means,said loosening means comprising conduit means communicating successivelywith said plurality of cells during relative movement of said strainermeans and said doctor'rneans,

so' as to thereby loosen said deposit of solid material on said firstface of said strainer means whereby the strained solid materialaccumulates in said upright containe to apply pressure to the suspensionof solid material deposited on said horizontal first face.

6. In a strainer apparatus, in combination, an upright municating withdifferent portions of the first face thereof; doctor means arrangedadjacent said first face of said strainer means and having a cleaningedge extending along the same; moving meansmoving one of said meansrelative to the other with said cleaning edge of said doctor meansmoving relative to and along said first face of said strainer means; andloosening means for receiving filtrate which has passed in said onedirection through said strainer means and forcing it back in theopposite direction from said second face through said strainer means tosaid first face thereof and in front of said cleaning edge of saiddoctor means, said loosening means being mounted in a position relativeto said doctor means for forcing filtrate out of said first face of saidstrainer means in front of the cleaning edge of said doctor means duringmovement thereof relative to said strainer means, said loosening meanscomprising conduit means communicating successively with said pluralityof cells during relative movement of said strainer means and said doctormeans, and pump means in said conduit means for forcing the filtratereceived by said conduit means back through said strainer means via therespective cell in communication with said conduit means, so as tothereby loosen said deposit of solid material on said first face of saidstrainer means whereby the strained solid material accumulates in saidupright container to apply pressure to the suspension of solid materialdeposited on said horizontal first face.

7. In a strainer apparatus, in combination, an upright container;strainer means arranged near the bottom'of said container and having ahorizontal first upwardly directed face on which a suspension of solidmaterial to, be strained is deposited, the filtrate passing in onedirection through said strainer means to the second face thereof and adeposit of strained solid material remaining on said first face of saidstrainer means, said strainer means having wall portions enclosing saidsecond face thereof and forming therewith a plurality of cellscommunicating with different portions of the first face thereof;filtrate chamber means arranged adjacent said strainer meanscommunicating with said cells thereof for receiving filtrate passingthrough said strainer means; doctor means arranged adjacent said firstface of said strainer means and having a cleaning edge extending alongthe same; moving means moving one of said means relative to the otherwith said cleaning edge of said doctor means moving relative to andalong said first face of said strainer means; and loosening means forreceiving filtrate which has passed in said one direction through saidstrainer means and forcing it back in the opposite direction from saidsecond face through said strainer means to said first face thereof andin front of said cleaning edge of said doctor means, said looseningmeans being mounted in a position relative to said doctor means forforcing filtrate out of said first face of said strainer means in frontof the cleaning edge of said doctor means during movement thereofrelative to said strainer means, said loosening means comprising conduitmeans communicating at its inlet end with said filtrate chamber meansand at its outlet end communicating successively with said plurality ofcells during relative movement of said strainer means and said doctormeans, and pump means in said conduit means for forcing the filtratereceived by said conduit means back through said strainer means via therespective cell in communication with said conduit means, so as tothereby loosen said deposit of solid material on said first face of saidstrainer means whereby the strained solid material accumulates in saidupright container to apply pressure to the suspension of solid materialdeposited on said horizontal first face.

8. In a strainer apparatus, in combination, an upright container;strainer means arranged near the bottom of said container and having ahorizontal first upwardly directed face on whicha suspension of solidmaterial to be strained is deposited, the filtrate passing in onedirection through said strainer means to the second face thereof spasmand a deposit of strained solid material remaining on said first face ofsaid strainer means, said strainer means having wall portions enclosingsaid second face thereof and forming therewith a plurality of cellscommunicating with different portions of the first face thereof;filtrate chamber means arranged adjacent said strainer meanscommunicating with said cells thereof for receiving filtrate passingthrough said strainer means; doctor means arranged adjacent said firstface of said strainer means and having a cleaning edge extending alongthe same;moving means moving one of said means relative to the otherwith said cleaning edge of said doctor means moving relative and alongsaid first face of said strainer means; loosening means for receivingfiltrate which has passed in said one direction through said strainermeans and forcing it back in the opposite direction from said secondface through said strainer means to said first face thereof and in frontof said cleaning edge of said doctor means, said loosening means beingmounted in a position relative to said doctor means for forcing filtrateout of said first face of said strainer means in front of the cleaningedge of said doctor means during movement thereof relative to saidstrainer means, said loosening means comprising conduit meanscommunicating at its inlet end with said filtrate chamber means forreceiving a portion of the filtrate therefrom and at its outlet endcommunicating successively with said plurality of cells during relativemovement of said strainer means and said doctor means, and pump means insaid conduit means for forcing the filtrate received by said conduitmeans back through said strainer means via the respective cell incommunication with said conduit means, so as to thereby loosen saiddeposit of solid material on said first face of said strainer meanswhereby the strained solid material accumulates in said uprightcontainer to apply pressure to the suspension of solid materialdeposited on said horizontal first face; and outlet means communicatingwith said filtrate chamber means for discharging the remainder of thefiltrate therefrom.

9. In a strainer apparatus, in combination, an upright container;strainer means arranged near the bottom of said container and having ahorizontal first upwardly directed face on which a suspension of solidmaterial to be strained is deposited, the filtrate passing in onedirection through said strainer means to the second face thereof and adeposit of strained solid material remaining on said first face of saidstrainer means, said strainer means having wall portions enclosing saidsecond face thereof and forming therewith a plurality of cellscommunicating with different portions of the first face thereof; doctormeans arranged adjacent said first face of said strainer means andhaving a cleaning edge extending along the same; rotating means rotatingsaid doctor means relative to said strainer means with said cleaningedge of said doctor means moving relative to and along said first faceof said strainer means; and loosening means for receiving filtrate whichhas passed in said one direction through said strainer means and forcingit back in the opposite direction from said second face through saidstrainer means to said first face thereof and in front of said cleaningedge of said doctor means, said loosening means being mounted in aposition relative to said doctor means for or facing filtrate out ofsaid first face of said strainer means in front of the cleaning edge ofsaid doctor means during movement thereof relative to said strainermeans, said loosening means comprising conduit means having an outletportion rotatable with said doctor means and communicating successivelywith said plurality of cells during relative movement of said strainermeans and said doctor means, and pump means in said conduit means forforcing the filtrate received by said conduit means back through saidstrainer means via the respective cell in communication with saidrotatable outlet portion of said conduit means, so as to thereby loosensaid deposit of solid material on said 9 first face ofsaid strainermeans whereby the strained solid-material accumulates in said uprightcontainer to apply pressure to the suspensir; n of solid materialdeposited on said horizontal first face.

10. In a strainer apparatus, in combination, an upright container;strainer means arranged near the bottom of said container and having ahorizontal first upwardly directed face on which a suspension of solidmaterial to be strained is deposited, the filtrate passing in onedirection through said strainer means to the second face thereof and adeposit of strained solid material remaining on said first face of saidstrainer means, said strainer means having wall portions enclosing saidsecond face thereof and forming therewith a plurality of cellscommunicating with different portions of the first face thereof; doctormeans arranged adjacent said first face of said strainer means andhaving a cleaning edge extending along the same; rotating means rotatingsaid strainer means relative to said doctor means withsaid cleaning edgeof said doctor means moving relative to and along said first face ofsaidstrainer means; and loosening means for receiving filtrate which haspassed in said one direction through said strainer means and forcing itback in the opposite direction from said second face through saidstrainer means to said first face thereof and in front of said cleaningedge of said doctor means, said loosening means beingmounted in aposition relative to said doctor means for forcing filtrate out of saidfirst face of saidstrainer means in front of the cleaning edge of saiddoctor means during movement thereof relative to said strainer means,said loosening means comprising stationary conduit means communicatingsuccessively with said plurality of cells during relative movement ofsaid strainer means and said doctor means, and pump means in saidconduit means for forcing the filtrate received by said conduit meansback through said strainer means via the respective cell incommunication with said conduit means, so as to thereby loosen saiddeposit of solid material on said first face of said strainer meanswhereby the strained solid material accumulates in said uprightcontainer-to apply pressure to the suspension of solid materialdeposited on said horizontal first face.

11. In a strainer apparatus, in combination, an upright containergstrainer means arranged-near the bottom of said container and having ahorizontal first upwardly directedfaceon which a suspension of solidmaterial to be strained is deposited, the filtrate passing in onedirection through said-strainer means to the second face thereof and adeposite of strained solid materialremaining on said first face of saidstrainer means, said strainer means having wallportions enclosing saidsecond face thereof and forming therewith aplurality of cellscommunicating-with'diiferent portions of the first face thereof;stationary filtrate chamber means arranged adjacent said strainer meanscommunicating with said cells thereof for receiving filtrate passingthrough said strainer means; doctormeans arranged adjacent said firstface of said strainer means and having a cleaning edge extending alongthe same; rotating means rotating said doctor means realtive to saidstrainer means with said cleaning-edge of-said doctor means movingrelative to and along said first face of said strainer means; andloosening means for receiving filtrate which has passed in said onedirection through saidstrainer means and forcing it back in the oppositedirection from said second face through said strainer means to. saidfirst face thereof and in front of said cleaning edge of said doctormeans, said loosening means being mounted in a position relative to saiddoctonmeans for forcing filtrate out of said first face of said strainermeans in front of the cleaning edge of said doctor means during movementthereof relative to said strainer means,-said loosening means comprisingconduit meanshaving an outlet portion rotatable with said doctor meansand-communicating at its inlet end with said catingsuccessively withsaid plurality of cells during relative movement of said strainer meansandsaid doctormeans, and pump mean: in said conduit means for forcingthe filtrate received by said conduit means back through said strainermeans via the respective cell in communication with said rotatableoutlet portion of said conduit means, so as to thereby loosen saiddeposit of solid material on said first face of said strainer meanswhereby the strainedsolid material accumulates in said upright containerto apply pressure to the suspension of solid material deposited on saidhorizontal first face.

12. In a strainer apparatus, in combination, an upright container;strainer means arranged near the bottom 'of said container and having ahorizontal first upwardly directed face on which a suspension ofsolid-material to be strained is deposited, the filtrate passing in onedirection through said strainer means to the second face thereof and adeposit of strained solid material remaining on said first face ofsaid-strainer means, said strainer means having Wall portions enclosingsaidsecond face thereof and forming therewith a plurality of cellscommunicating with different portions of the first face thereof;stationmy filtrate chamber means arranged adjacent said strainer meanscommunicating with said cells thereof for receiving filtrate passingthrough said strainer means; doctor means arranged adjacent said firstface of said strainer means and having a cleaning edge extending alongthe same; rotating means rotating said doctor means relative to saidstrainer means with said cleaning edge of said doctor means movingrelative to and along said first face of said strainer means;'loosen.ing means for receiving filtrate which has passed in said one directionthrough said strainer means and forcing it back in the oppositedirection from said second face through said strainer means to saidfirst face thereof and in-front of said cleaning edge of'said doctormeans, said loosening means being mounted in a position relative to saiddoctor means for forcing filtrate out of said first face of saidstrainer means in front of the cleaning edge of said doctor means duringmovement thereof relative to said strainer means, said loosening meanscomprising conduit means having an outlet portion rotatable with saiddoctor means and communicating at its inlet and with said fiitratechamber means for receiving the portion of the filtrate therefrom and atits outlet end communicating successively with said plurality ofcellsduring relative movement ofsaid strainer means and said doctor means,and pump means in said conduit means for forcing the filtrate receivedby said conduit means back through said strainermeans via the respectivecell in communication with said rotatable outlet portion of said conduitmeans so as to thereby loosen said deposit of solid material on saidfirst'face of said strainer means whereby the strained solid materialaccumulates in said upright container to apply pressure to thesuspension of solid material deposited on said horizontal first face;'

and outlet means communicating with said filtrate chamber means fordischarging the remainder of the filtrate therefrom.

13. In a strainer apparatus, in combination, an upright container;strainer means arranged near the bottom of saidcontainer and having ahorizontal first upwardly directed face on which a suspension of solidmaterial to'be strained is deposited, the filtrate passing in onedirection through said strainer means'to the second face thereof andadeposit of strained solid material remaining on said first face of saidstrainer means, said strainer means having wall portions enclosing saidsecond face thereof and forming therewith a plurality of cellscommunicating with different portions of the first face thereof;stationary filtrate chamber means arranged adjacent said strainer meanscommunicating with said cells thereof for receiving filtrate passingthrough said strainer means; doctor means arranged adjacent said firstface of said strainer filtrate chamber means and at its outlet endcommunimeans and having a cleaning edge extending along the same;rotating means rotating said strainer means relative to said doctormeans with saidcleaning edge of said doctor means moving relative to andalong said first face of said strainer means; and loosening means forreceiving filtrate which has passed in said one direction through saidstrainer means and forcing it back in the opposite direction from saidsecond face through said strainer means to said first face thereof andin front of said cleaning edge of said doctor means, said looseningmeans being mounted in a position relative to said doctor means forforcing filtrate out of said first face of said strainer means in frontof the cleaning edge of said doctor means during movement thereofrelative to said strainer means, said loosening means comprisingstationary conduit means communicating at its inlet end with saidfiltrate chamber means and at its outlet end communicating successivelywith said plurality of cells during relative movement of said strainermeans and said doctor means, and pump means in said conduit means forforcing the filtrate received by said conduit means back through saidstrainer means via the respective cell in communication with saidconduit means, so as to thereby loosen said deposit of solid material onsaid first face of said strainer means whereby the strained solidmaterial accumulates in said upright container to apply pressure to thesuspension of solid material deposited on said horizontal first face.

14. In a strainer apparatus, in combination, an upright container;strainer means arranged near the bottom of said container and having ahorizontal first upwardly directed face on which a suspension of solidmaterial to be strained is deposited, the filtrate passing in onedirection through said strainer means to the second face thereof and adeposit of strained solid material remaining on said first face of saidstrainer means, said strainer means having wall portions enclosing saidsecond face thereof and forming therewith a plurality of cellscommunicating with different portions of the first face thereof;stationary filtrate chamber means arranged adjacent said strainer meanscommunicating with said cells thereof for receiving filtrate passingthrough said strainer means; doctor means arranged adjacent said firstface of said strainer means and having a cleaning edge extending alongthe same; rotating means rotating said strainer means relative to saiddoctor means with said cleaning edge of said doctor means movingrelative to and along said first face of said strainer means; looseningmeans for receiving filtrate which has passed in said one directionthrough said strainer means and forcing it back in the oppositedirection from said second face through said strainer means to saidfirst face thereof and in front of said cleaning edge of said doctormeans, said loosening means being mounted in a position relative to saiddoctor means for forcing filtrate out of said first face of saidstrainer means in front of the cleaning edge of said doctor means duringmovement thereof relative to said strainer means, said loosening meanscomprising stationary conduit means communicating at its inlet end withsaid filtrate chamber means for receiving a portion of the filtratetherefrom and at its outlet end communicating successively with saidplurality of cells during relative movement of said strainer means andsaid doctor means, and pump means in said conduit means for forcing thefiltrate received by said conduit means back through said strainer meansvia the respective cell in communicating with said conduit means, so asto thereby loosen said deposit of solid material on said first face ofsaid strainer means whereby the strained solid material accumulates insaid upright container to apply pressure to the sus: pension of solidmaterial deposited on said horizontal first face; and outlet meanscommunicating with said filtrate chamber means for discharging theremainder of the filtrate therefrom.

15. In a strainer apparatus, in combination, an upright container;strainer means arranged near the bottom of said container and having ahorizontal first upwardly directed face on which a suspension of solidmaterial to be strained is deposited, the filtrate passing in onedirection through said strainer means to the second face thereof and adeposit of strained solid material remaining on said first face of saidstrainer means; container means extending around said first face of saidstrainer means for receiving a suspension of solid material to bedeposited on said strainer means; inlet means connected to saidcontainer means for introducing a suspension of solid material therein;doctor means arranged in said container means adjacent said first faceof said strainer means and having a cleaning edge extending along thesame; moving means moving one of said means relative to the other withsaid cleaning edge of said doctor means moving relative to and alongsaid first face of said strainer means; loosening means for forcing aportion of the filtrate which has passed in said one direction throughsaid strainer means back in the opposite direction from said second facethrough said strainer means to said first face thereof and in front ofsaid cleaning edge of said doctor means, said loosening means beingmounted in a position relative to said doctor means for forcing filtrateout of said first face of said strainer means in front of the cleaningedge of said doctor means during movement thereof relative to saidstrainer means, so as to thereby loosen said deposit of solid materialon said first face of said strainer means; and outlet means fordischarging the remainder of said filtrate whereby the strained solidmaterial accumulates in said upright container to apply pressure to thesuspension of solid material deposited on said horizontal first face.

16. In a strainer apparatus, in combination, an upright container;strainer means arranged near the bottom of said container and having ahorizontal first upwardly directed face on which a suspension of solidmaterial to be strained is deposited, the filtrate passing in onedirection through said strainer means to the second face thereof and adeposit of strained solid material remaining on said first face of saidstrainer means; container means extending around said first face of saidstrainer means for receiving a suspension of solid material to bedeposited on said strainer means; inlet means connected to saidcontainer means for introducing a suspension of solid material therein;doctor means arranged in said container means adjacent said first faceof said strainer means and having a cleaning edge extending along thesame; moving means moving one of said means relative to the other withsaid cleaning edge of said doctor means moving relative to and alongsaid first face of said strainer means; filtrate chamber means forreceiving filtrate from said strainer means; loosening means for forcinga portion of the filtrate in said filtrate chamber means which haspassed in said one direction through said strainer means back in theopposite direction from said second face through said strainer means tosaid first face thereof and in front of said cleaning edge of saiddoctor means, said loosening means being mounted in a position relativeto said doctor means for forcing filtrate out of said first face of saidstrainer means in front of the cleaning edge of said doctor means duringmovement thereof relative to said strainer means, so as to therebyloosen said deposit of solid material on said first face of saidstrainer means; and outlet means connected to said filtrate chambermeans for discharging the remainder of said filtrate therein whereby thestrained solid material accumulates in said upright container to applypressure to the suspension of solid material deposited 'on saidhorizontal first place.

17. In a strainer apparatus, in combination, an upright container;strainer means arranged near the bottom of said container and having ahorizontal first upwardlydirected face on which a suspension of solidmaterial to be strained is deposited, the filtrate passing in onedirection through said strainer means to the second face thereof and adeposit of strained solid material remaining on saidfirstface ofsaidstrainermeans, said strainer means having Wall portions enclosingsaid second face thereof and forming therewiLh a plurality of cellscommunicating with different portions of the first face thereof;container means extending around'said first'face of said strainer meansfor receiving a suspensionof solid material to be deposited on saidstrainer means; inlet meansconnected to said container means forintroducing a suspension of solid material therein; doctor meansarranged in said container means adjacent said first face of saidstrainer means and having acleaning edge extending along the same;moving means moving one of said means relative to the other with saidcleaning edge of said doctor means moving relative to and along saidfirst face of said strainer means; loosening means for receiving aportion of the filtrate which has passed in said one direction throughsaid strainer means and forcing it back in the opposite direction fromsaid second face through said strainer means to said first face thereofand in front of said cleaning edge of said doctor means,

said loosening means being mounted in a position relative to said doctormeans for forcing filtrate out of said first face of said strainer meansin front of the cleaning edge of said doctor means during movementthereof relative to said strainer means, said loosening means comprisingconduit means communicating successively with said plurality of cellsduring relative movement of said strainer means and said doctor means,so as to thereby loosen said deposit of solid material on said firstface of said strainer means whereby the strained solid materialaccumulates in said upright container to apply pressure to thesuspension of solid material deposited on said horizontal first face;and outlet means for discharging the remainder of said filtrate.

18. In a strainer apparatus, in combination, an upright container;strainer means arranged near the bottom of said container and having ahorizontal first upwardly directed face on which a suspension of solidmaterial to be strained is deposited, the filtrate passing in onedirection through said strainer means to the second face thereof and adeposit of strained solid material remaining on said first face of saidstrainer means, said strainer means having wall portions enclosing saidsecond face thereof and forming therewith a plurality of cellscommunicating with different portions of the first face thereof;container means extending around said first face of said strainer meansfor receiving a suspension of soild material to be deposited on saidstrainer means; inlet means connected to said container means forintroducing a suspension of solid material therein; doctor meansarranged in said container means adjacent said first face of saidstrainer means and having a cleaning edge extending along the same;rotating means rotating said doctor means relative to said strainermeans with said cleaning edge of said doctor means moving relative toand along said first face of said strainer means; loosening means forreceiving a portion of the filtrate which has passed in said onedirection through said strainer means and forcing it back in theopposite direction from said second face through said strainer means tosaid first face thereof and in front of said cleaning edge of saiddoctor means, said loosening means being mounted in a position relativeto said doctor means for forcing filtrate out of said first face of saidstrainer means in front of the cleaning edge of said doctor means duringmovement thereof relative to said strainer means, said loosening meanscomprising conduit means communicating successively with said pluralityof cells during relative movement of said strainer means and said doctormeans, so as to thereby loosen said deposit of solid material on saidfirst face of said strainer means whereby the strained solid materialaccumulates in said upright container to apply pressure to thesuspension of solid material deposited on said horizontal first face;and outlet means for discharging the remainder of said filtrate,

19. -In-a'strainer apparatus,in combination, an upright container;strainer means arranged nearthe bottom of said container and having ahorizontal'first upwardly directed face on which a suspension of solidmaterial to be strained is deposited, the filtrate passin'g'in onedirection through said strainer means to the second face thereof-andadeposit of strained solid material remaining on said first face of saidstrainer means, said strainer means having wall portions enclosing saidsecond face thereof and forming therewith a plurality of cellscommunicating with different portions of the first face thereof;container means extending around said first faceof said strainer-meansforreceiving a suspension" of solid material to be deposited on saidstrainer means; inlet means connected to said container means forintroducing a suspension of solid material therein; doctor meansarranged in said container means adjacent said first face of saidstrainer means and having a cleaning edge extending along the same;rotating means rotating said strainer means relative to said doctormeans with said cleaning edge of said doctor means moving relative toand along said first face of said strainer means; loosening means forreceiving a portion of the filtrate which has passed in said onedirection through said strainer means and forcing it back in theopposite direction from said second face through said strainer means tosaid first face thereof and in front of said cleaning edge of saiddoctor means, said loosening means being mounted ina position relativeto said doctor means for forcing filtrate out of said first face of saidstrainer means in front of the cleaning edge of said doctor means duringmovement thereof relative to said strainer means, said loosening meanscomprising conduit means communicating successively with said pluralityof cells during relative movement of said strainer means and said doctormeans, so as to thereby loosen said deposit of solid material on saidfirst face of said strainer means whereby the strained solid materialaccumulates in said upright container to apply pressure to thesuspension of solid material deposited on said horizontal first face;and outlet means for discharging the remainder of said filtrate.

20. In a strainer apparatus, in combination, an upright container;strainer means arranged near the bottom of said container and having ahorizontal first upwardly directed face on which a suspension of solidmaterial to be strained is deposited, the filtrate passing in onedirection through said strainer means to the second face thereof and adeposit of strained solid material remaining on said first face of saidstrainer means, said strainer means having Wall portions enclosing saidsecond face thereof and forming therewith a plurality of cellscommunicating with different portions of the first face thereof;container means extending around said first face of said strainer meansfor receiving a suspension of solid material to be deposited on saidstrainer means; inlet means connected to said container means forintroducing a suspension of solid material therein; filtrate chambermeans arranged adjacent said strainer means communicating With saidcells thereof for receiving filtrate passing through said strainermeans; doctor means arranged in said container means adjacent said firstface of said strainer means and having a cleaning edge extending alongthe same; moving means moving one of said means relative to the otherwith said cleaning edge of said doctor means moving relative to andalong said first face of said strainer means; loosening means forreceiving a portion of the filtrate which has passed in said onedirection through said strainer means and forcing it back in theopposite direction from said second face through said strainer means tosaid first face thereof and in front of said cleaning edge of saiddoctor means, said loosen-.

ing means being mounted in a position relative to said doctor means forforcing filtrate out of said first face of said strainer means in frontof the cleaning edge of said doctor means during movement thereofrelative to said strainer means, said loosening means comprising conduitmeans communicating at its inlet end with said filtrate chamber meansand at its outlet end communicating successively with said plurality ofcells during relative movement of said strainer means and said doctormeans, and pump means in said conduit means for forcing the filtratereceived by said conduit means back through said strainer means via therespective cell in communication with said conduit means, so as tothereby loosen said deposit of solid material on said first face of saidstrainer means whereby the strained solid material accumulates in saidupright container to apply pressure to the suspension of solid materialdeposited on said horizontal first face; and outlet means connected tosaid filtrate chamber means for discharging the remainder of saidfiltrate.

References Cited in the file of this patent UNITED STATES PATENTS PowellNov. 8, Bird Dec. 26, Malone Ian. 16, Brown Feb. 27, McNeal Oct. 6,Wanner et a1. Jan. 6, MacNeil Feb. 9, Selensky July 3,

FOREIGN PATENTS Germany Oct. 15, Great Britain Aug. 14,

